btrfs: lock the inode in shared mode before starting fiemap

{
  "id": "667d2315d748bb2b44dea41f1ab19537d847c0cd04c5be00a7cfdb14e4d1a33e",
  "url": "https://osv.dev/vulnerability/CVE-2023-52737",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: lock the inode in shared mode before starting fiemap",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: lock the inode in shared mode before starting fiemap Currently fiemap does not take the inode's lock (VFS lock), it only locks a file range in the inode's io tree. This however can lead to a deadlock if we have a concurrent fsync on the file and fiemap code triggers a fault when accessing the user space buffer with fiemap_fill_next_extent(). The deadlock happens on the inode's i_mmap_lock semaphore, which is taken both by fsync and btrfs_page_mkwrite(). This deadlock was recently reported by syzbot and triggers a trace like the following: task:syz-executor361 state:D stack:20264 pid:5668 ppid:5119 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5293 [inline] __schedule+0x995/0xe20 kernel/sched/core.c:6606 schedule+0xcb/0x190 kernel/sched/core.c:6682 wait_on_state fs/btrfs/extent-io-tree.c:707 [inline] wait_extent_bit+0x577/0x6f0 fs/btrfs/extent-io-tree.c:751 lock_extent+0x1c2/0x280 fs/btrfs/extent-io-tree.c:1742 find_lock_delalloc_range+0x4e6/0x9c0 fs/btrfs/extent_io.c:488 writepage_delalloc+0x1ef/0x540 fs/btrfs/extent_io.c:1863 __extent_writepage+0x736/0x14e0 fs/btrfs/extent_io.c:2174 extent_write_cache_pages+0x983/0x1220 fs/btrfs/extent_io.c:3091 extent_writepages+0x219/0x540 fs/btrfs/extent_io.c:3211 do_writepages+0x3c3/0x680 mm/page-writeback.c:2581 filemap_fdatawrite_wbc+0x11e/0x170 mm/filemap.c:388 __filemap_fdatawrite_range mm/filemap.c:421 [inline] filemap_fdatawrite_range+0x175",
    "evidence": "osv:CVE-2023-52737",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.13",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-52737",
      "aliases": [
        "CVE-2023-52737"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "885f46d87f29a94eafe3cc707d5c4dea2be248f3"
                },
                {
                  "fixed": "e425191073a80906d8502b5179471cc58b0b9e9a"
                },
                {
                  "fixed": "d8c594da79bc0244e610a70594e824a401802be1"
                },
                {
                  "fixed": "519b7e13b5ae8dd38da1e52275705343be6bb508"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52737.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.13.0"
                },
                {
                  "fixed": "5.15.209"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.13"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52737.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.788668463Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/519b7e13b5ae8dd38da1e52275705343be6bb508",
        "https://git.kernel.org/stable/c/d8c594da79bc0244e610a70594e824a401802be1",
        "https://git.kernel.org/stable/c/e425191073a80906d8502b5179471cc58b0b9e9a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52737.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-52737",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52737.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-52737",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505047,
  "published_at": "2024-05-21T15:23:01.202+00:00"
}